Facile synthesis of Fe3O4@polyethylenimine with peroxidase-like activity for highly sensitive detection of interferon α-2b

The sensitive detection of interferon alpha-2b (IFN-α2b) is crucial in treating viral infections and cancers. However, the natural enzymes used in the traditional enzyme-linked immunosorbent assays (ELISA) face the obstacles of high cost and low stability. Therefore, there is an urgent need to develop more cost-effective and stable alternatives to detect IFN-α2b. To address this issue, we synthesized poly-ethyleneimine (PEI)-modified magnetic nanoparticles (Fe3O4@PEI MNPs) that are highly stable, affordable and simple to prepare. These Fe3O4@PEI MNPs serve as a substitute for horseradish peroxidase in the ELISA-based detection of IFN-α2b, providing better sensitivity than chromatographic and traditional ELISA techniques. The peroxidase-like activity of Fe3O4@PEI MNPs can develop color, enabling the visualization of IFN-α2b. The proposed immunoassay has a linear increase with IFN-α2b concentrations ranging from 0.075 to 25 ng mL−1, with a low limit of detection of 0.055 ng mL−1. Based on the outstanding peroxidase-like activity of Fe3O4@PEI MNPs, this method has the potential to be used for the clinical detection of IFN-α2b and other protein biomarkers in disease diagnosis and treatments.